未来气候变化对淮河流域径流的可能影响

Impact of Climate Change on Runoff in the Huaihe River Basins

采用新安江月分布式水文模型,结合1961—2000年历史月气候资料和4个CGCMs的3个SRES排放情景下(B1,A2,A1B)未来降水和气温情景模拟结果,对过去淮河流域的径流进行模拟检验并对未来2011—2040年的径流影响进行评估,为水资源管理和规划提供依据。结果表明:水文模型能较好地反映年、月流量以及多年平均值和季节的变化;年流量模拟一般好于月流量,淮河干流主要控制水文站如王家坝、鲁台子、蚌埠的年流量模型效率系数均在80以上;多年平均值模拟效果好,平均绝对相对误差为10。多数CGCMs不同排放情景下气候模拟结果表明:未来2011—2040年,淮河流域气候将趋于暖湿,但年径流量将可能以减少趋势为主。这对淮河地区水资源的可持续发展以及东线调水工程水资源统一调配和管理提出了较大的挑战。淮河流域大部分区域2011—2040年月径流量减少将主要发生在1月和7—12月,变化趋势较为确定;4—6月,径流量将以增加趋势为主,不确定性较大;2—3月,径流具有增加趋势的地区多分布在淮河以北地区,具有减少趋势的地区则多分布在淮河干流及以南地区和洪泽湖、平原区,这些地区增加或减少趋势的不确定性较大。

The assessment about future climate change on runoff of the The Xin＇anjiang monthly distributed hydrological model is used Huaihe River Basins to simulate the past in China is focused. and future runoffs. The model is run with observed monthly precipitation and air temperature during 1961-2000 and the simulated runoff is verified with the corresponding hydrological observations. The verifications show that annual and monthly runoff are simulated well and the Nash efficiency coefficients range from 60G to 80 for the monthly simulations but above 80% for annual runoff at major hydrological stations such as Wangjiaba, Lutaizi and Bengbu. For runoff average in many years, the simulation is better. The correlation coefficient between simulations and observations reaches 0.99 and the mean absolute relative error is about 10G. The verified model is then forced with future climate scenarios based on three emission ones （B1, A2 and A1B） during 2011 2040 period from four coupled atmospheric and oceanic general circulation models to simulate future changes in the runoff. In the simulated future, the climate of Huaihe River Basins will be warmer and more humid compared with the climate of the base period of 1961--1990. Future annual runoff in the periods would have decreasing trends, which poses a challenge to the sustainable development of the Huaihe River Basins and water management of the East Route in the South-north Division Project. Monthly runoff would decrease in January and from July to December with high certainty and to increase during April to June with high uncertainty in most area of the Huaihe River Basin. During Febru- ary and March, the monthly runoff would increase in the north of the Basin and to decrease in the south area to the stem of the Huaihe River as well as the Hongze Lake and the plain area of lower reaches of the Huaihe River.